Here's the ChaosEsque wishlist for the engine, with X next to finished works
[x]More entity support
[x]Wolfenstine:Enemy Territory map support
BZFlag map support (.bzw) (opensource project)
Design It 3D! map support
Unreal 97 map support (Quake Army Knife opensource has this code)
UnrealTournament 99 map support (ditto)
procedural terrain, including procedural LOD
volumetric "block" terrain, but higher quality like in 7 days to die
PlanetSide2 map support
And for the Gamecode
[/] procedural map generation (spawnarrays, spawnradials done)
parsing simcity 2k maps (opensource lua code exists for this) (could be done engine wise too, up against limit for globals in QC (everything is a global) 65k)
models_shared.c and models_shared.h are where the definitions/code for loading new models is. Mod_OBJ is a good starting point, then search for "obj" to find the magic-file-type-determinator code in there to point to the new function. (in the case of obj it just assumes it's an obj if the file ends with .obj)
The engine code is on the iso you all download.
git_repos_both.zip.